A solid electrolytic capacitor includes a capacitor element comprising a positive electrode made of valve metal, a positive electrode lead having a first end portion embedded in the positive electrode and a second end portion protruding from the positive electrode, a dielectric layer formed by anodizing the positive electrode and a part of the positive electrode lead, an electrolyte layer formed on the dielectric layer, and a negative electrode extracting layer formed on the electrolyte layer.
The first end portion of the positive electrode lead is embedded in a molded product made of powder of the valve metal with the second end portion protruding therefrom, and the molded product is sintered, so that the positive electrode and the positive electrode lead are integrally formed with each other.
In a solid electrolytic capacitor in which a positive electrode lead is embedded in a positive electrode, in a process of producing the solid electrolytic capacitor, stress is applied to a root portion of the positive electrode lead, and leakage current is increased in this portion.
Japanese Patent Application Unexamined Publication No. 2003-338432 proposes that leakage current be reduced by making a film thickness of a dielectric layer in the vicinity of a root portion of a positive electrode lead larger than a film thickness of the dielectric layer in the other portion.